The production of fibre reinforced thermosetting plastic products can be automatized by the use of an industrial robot, by means of which a fibre feed apparatus can be controlled, so that precise amounts of fibers are fed out which are oriented for maximum strength, without the fibers projecting out through the outer plastic layer of the product. Owing to the repeatability of the robot, the quality of these products can be increased considerably, simultaneously as problems related to bad work environment and labor fatigue can be solved.
The fibre feeding apparatus is preferably located in a feedout head which can be mounted upon a movable robot arm. One or more fibre threads are supplied to the feedout head, which cuts the threads in suitable lengths. The feeding speed of the fibre thread can be in the range of about 10 meters per second. At such a feeding speed, it is difficult to stop the feeding of thread without any risk of getting the thread tangled.
The features defined in the above mentioned older application solve in an efficient manner the problems defined above.
However it has proven itself that there can still occur some risk for entanglement when the yoke provided with the movable thread guide moves downwards at a high speed. When the yoke then reaches its lower position there might be a bounce making the fed fibre thread slacken and become tangled.
The Technical Problem
The object of the invention is therefore to provide an arrangement at a thread feeding buffer which solves the above described problem.
The Solution
For this purpose the entangling protection arrangement for a thread feeding buffer for a fibre thread fed from a supply and along a path comprising a first guide for the thread, for receiving the thread from the supply, a contactable brake surface over which the thread is fed from the first guide; a brake element movement into control with the brake surface for bracking movement of the thread past the brake surface; a moveable thread guide in the path of the thread past the brake surface, a support comprising two substantially vertically arranged guide rods supporting the movable thread guide for movement; a further guide following the movable thread guide in the path of the thread and past which the thread is draw; the support enabling the movable thread guide to be moved by the thread to reduce the length of the thread path between the brake element engaging the brake surface and also permitting the movable thread guide to move to lengthen the distance between the brake surface and the further thread guide to absorb slack in the thread on the path between the brake surface and the further thread guide, is characterized in that at least one of said guide rods is provided with means arranged to cause a braking effect on downward movement of the movable thread guide for preventing entanglement of the thread fed through the movable thread guide following a rapid fall of said movable thread guide.